JPS63233390A - Radar jamming instrument - Google Patents

Abstract

PURPOSE:To apply a frequency-modulation to a jamming signal only in a condition wherein the time delay of the jamming signal is larger than the range gate of a radar by adding a circuit for judging the execution or the stopping of the frequency modulation in accordance with the time delay of the jamming signal. CONSTITUTION:A delay time control circuit 3 obtains a delay time to be given to an input pulse signal and feeds signals to a delay circuit 2 and a frequency modulation execution judging circuit 7. The delay circuit 2 feeds a delay signal with the time delay to a path changeover switch 6 in response to the pulse signal inputted from a received signal input terminal 1. On the other hand, the judging circuit 7 outputs a signal (a) to the switch 6 when the delay time to be given to the input signal is larger than the range gate of a radar and otherwise outputs a signal (b). The switch 6 feeds the delay signal to an amplitude modulating circuit 4 in case of the signal (a) or to a jamming signal output terminal 5 in case of the signal (b). The modulation circuit 4 applies a prescribed amplitude modulation to the delay signal in case of the signal (a) and outputs the modulated delay signal to the output terminal 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radar jamming device that transmits jamming waves to a radio wave emission source such as a radar.

[Conventional technology]

FIG. 2 is a configuration diagram showing a conventional radar jamming device. In the figure, Ill is a received signal input terminal, (21 is a delay circuit that applies a sufficient time delay to the input received signal, (
31 is a delay time control circuit 4 that instructs the delay time to this delay circuit (2), 141 is a delay circuit (an amplitude modulation circuit that performs interpupillary width modulation on the delayed signal outputted by !1, ; 11) is an interference signal It is an output terminal.

Next, the operation will be explained.

Now, consider the case where the pulse signal train shown in FIG. 3 is input to the received signal input terminal. The delay time control circuit (31 is the delay time (d) to be given to the incoming signal at the relevant time
t) and sends it to the delay circuit 121. Fourth
The figure shows an example of time 611 change in delay time. Delay circuit (21
is the received signal input terminal Ill f! : A delayed signal having a time delay of dt with respect to the input pulse signal is sent to the amplitude modulation circuit (41).

The amplitude modulation circuit (41 performs amplitude modulation on the delayed signal and then sends it to the interference signal output terminal +51).

Since the above operation is performed every time a pulse signal is input, both the radar echo signal and the interference signal are input to the radar, which is the object of interference. FIG. 5 shows an example of the radar side input signal. In Figure 5, +al is when the time delay of the jamming signal is smaller than the radar range gate? It shows.

This corresponds to the range A in FIG. l! In state I, both the radar echo signal and the interference signal are present within the distance gate of the radar, and a normal radar generally tracks the signal with a large range within the distance gate. , in order to cause the radar to follow the jamming signal K jA, the amplitude of the jamming signal must always be greater than the amplitude of the total radar echo signal. After the radar tracks the jamming signal.

By gradually increasing the delay time as shown by the arrow B in Figure 4, the radar distance gate will move to the rear of the radar echo signal as shown in Ib+ in Figure 5. . In VC of FIG. 5, (0) C indicates a case where the time delay of the interference signal is larger than the distance gate of the radar, and corresponds to the range C of FIG. 4. Since only the interference signal exists within the range gate of the radar, it is possible to give a interference effect to the radar by applying amplitude modulation to the interference signal VC.

[Problem that the invention seeks to solve]

Conventional radar jamming devices change the amplitude fA of the jamming signal even when the time delay of the jamming signal is smaller than the radar distance gate.
There was a problem in that it was difficult to separate it from the echo signal, and it did not produce any interference effect.

The present invention has been made to solve the above-mentioned problems, and aims to provide a radar jamming device that performs amplitude modulation on a jamming signal only when the time delay of the jamming signal is larger than the sparsity gate of the radar. purpose.

[Problem t-Means for solving]

The radar jamming device according to the present invention differs from the conventional radar jamming device in that it has a circuit that determines whether to perform or stop amplitude modulation according to the time delay of the jamming signal. That's what I added.

[Effect]

The amplitude modulation execution determination circuit in the present invention inputs a time delay 72 to the received signal from the delay time control circuit, and inputs the delayed signal to the amplitude modulation circuit only when the one-hour delay is larger than the distance gate of the radar. Control.

[Embodiments of the invention]

Hereinafter, FIG. 2 will be described as an embodiment of the present invention. 1st
In the figure, ... is a received signal input terminal, and a delay circuit (,3;
A delay time 'MI control circuit for controlling the delay time of the tobacco delay circuit 121 (61 is a path changeover switch for switching the transmission path of the delayed signal outputted by the delay circuit (21); Route changeover switch (amplitude modulation execution determination circuit that sends a switching signal to 61; 41 is an amplitude modulation circuit that performs amplitude modulation on the delayed signal input via the route changeover switch; +61 is an interference signal that outputs an interference signal) It is an output terminal.

Next, the operation will be explained.

Now, the pulse signal train shown in FIG. 3 is connected to the received signal input terminal II.
Consider the case of inputting to +. The delay time system circuit 131 determines the delay time (6t>) to be given to the input pulse signal at the relevant time and sends it to the delay circuit 12 and the amplitude modulation implementation determination circuit (7).

FIG. 4 shows an example of how the delay time changes over time.

The delay circuit 121 sends a delayed signal having a time delay of at to the pulse signal inputted through the received signal input terminal +11'i to the path changeover switch (81).On the other hand, the amplitude modulation implementation determination circuit (7) If at is larger than the distance gate of the radar (range A in FIG. 4), the VC sends a 1a1 signal to the path changeover switch 16), otherwise it sends an lb° signal.

The path changeover switch (61 sends out the delayed signal to the amplitude modulation circuit 141 in the case of the 1a1 signal, and sends out the delayed signal to the interference signal output terminal 151 in the case of the +1., l signal.Amplitude modulation circuit 141 After subjecting the delayed signal to a predetermined amplitude modulation, it is sent to the interference signal output terminal 5).

〔Effect of the invention〕

As described above, according to the present invention, the amplitude change t4 is applied to the jamming signal only when the time delay of the jamming signal with respect to the received signal is larger than the distance gate of the radar.
Amplitude modulation of the interference signal is no longer performed within the range gate of the radar, and the radar tracks the interference signal (interference occurs on the radar).6 (The higher the g rate, the more effective it is.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a radar jamming device according to an embodiment of the present invention, Fig. 2 is a block diagram of a conventional radar jamming device, Fig. 3 is an input pulse signal train, and Fig. 4 is an example of time variation of delay time. ,
1. FIG. 5 is an example of the input signal situation on the radar side. In 1'AVC, the peaks are the received signal input terminals, (21 is the delay circuit, 131-digit delay time control circuit, 141 is the amplitude modulation circuit, (6) is the interference signal output terminal, (8) is the path changeover switch, ( 7) is an interpupillary distance modulation execution determination circuit. In the drawings, the same reference numerals indicate the same or the contact portions.

Claims (1)

[Claims] A device that transmits a disturbance signal subjected to amplitude modulation after an appropriate time delay with respect to a received signal, characterized by being provided with a circuit that controls execution/stop of amplitude modulation according to the time delay of the disturbance signal. Radar jammer.